The present invention relates, in general, to forming of component leads, and more particularly to forming of package leads for semiconductor components.
One of the critical steps in the manufacture of a semiconductor component is the forming of package leads into their final shape. This operation is particularly critical since it takes place as one of the final steps of a complex multi-step process. A single damaged lead in a multiple lead package results in scrapping of an otherwise useable and expensive component. The small size of many packages makes precise formation of leads essential, yet the operation must be performed rapidly so as not to add unduly to the product cost. The advent of surface mounted technology (SMT) has further complicated this problem since multiple bends in these critical leads are now required. Typical packages for the smallest components are approximately 2 mm by 1.25 mm by 0.9 mm making any manual handling of individual components a difficult task. In the past, a hydraulic press has been used to bend the leads after the components have been separated from the lead frame by a separate cutting process. This requires that individual components be handled both before the leads are formed as well as afterwards. Because of the small size and tight tolerances required, it is difficult to locate the separated components on the press precisely enough to achieve the required final form dimensions. Finally, the motion of the former die past the leads may cause "smearing" of the lead surface, damaging the lead and causing the entire semiconductor component to be scrapped.
There is a need for a method to bend semiconductor component leads into their final shape which is fast, accurate, and does not have the potential to damage the leads or the component during the forming process. Preferably the method would allow the components to be handled in bulk as much as possible to minimize the difficult handling of small components.